Carburetor



Oct. 11, 1932. a. M. BICKNELL CARBURETOR Filed Feb. 21, 1929 3Sheets-Sheet INVENTOR A'IORNEY Oct. 11, 1932. (57 M. BICKNELL CARBURETOR5 Sheets-Sheet 2 Filed Feb. 21, 1929 g E /7 MVV/V 7 7 j j INVENTORI BY mATTORNEY Patented Oct. 11, 1932 UNITED STATES PATENT 'OFFICECORPORATION, OF ST. LOUIS, MISSOURI, A CORPORATION OF DELAWAREcaannan'roa Application filed February 21, 1929. Serial 1104341331.

This invention relates to carburetors, and

particularly to carburetors of the type in which a pump is provided forsupplying an extra uantity of gasoline during acceleration. uch pumpsare usually connected to the throttle to be operated upon an openingmovement thereof, and when the throttle 1s once fully opened to thedesired pos1tion, the additional supply of gasoline is lmmediatelydiscontinued, leaving only the normal supply in operation. Asconsiderable time is required after the opening of the throttle for theengine to overcome the inertia of the car and bring it up to the properspeed, it 1s desirable to continue the extra supply of gasoline for afew seconds after the throttle has been opened. As carburetors areusually adjusted to operate satisfactorily under all weather conditions,it is customary to adjust them to give a considerably richer mixturethan is necessary or desirable after the engine has thoroughly warmedup. The supply of an addltional quantity of gasoline to the mixingchamber, such as that delivered by the pump, accordingly becomes lessnecessary and de sirable after the engine has warmed up, and at very.high temperatures might cause loading of the engine due to excess fuel.

One of the objects of this invention is to provide an accelerating pumpof simple and reliable construction for supplying additional quantitiesof fuel upon an opening movement of the throttle and for continuing theadditional supply for a few seconds after the opening movement of thethrottle has ceased.

Another object of this invention is to provide a pump suitable for thefirst-named purpose of such design and construction that a thermostaticcontrol means may be readily applied thereto for reducing theeffectiveness of the pump at high temperatures.

The invention will be better understood upon reference to theaccompanying-drawings, in which:

Figure 1 is a front elevation of one form of carburetor embodying myinvention, with parts broken away for better illustration of others.

Figure 2 is a side elevation of the carburetor shown in Figure l withparts shown in cross section on the line 2-2 of Figure 1.

Figure 3 is a sectional view taken along lines 3-3 of Figure 2, lookingin the direction of the arrows.

Figure 4 is a detail View showing parts of the pump piston andthermostat control in cross section.

Figure 5 shows an elevation of a modified form of carburetor having myinvention applied thereto.

Figure 6 is a somewhat diagrammatic sectional view of the form ofcarburetor shown in Figure'5.

Figure 7 is a cross sectionalview of a modified form of acceleratingpump.

The reference numeral 1 indicates a casting forming the body member ofthe carburetor, a sheet metal bowl 2 is attached to the lower part ofthe body member by a nut 3. The body member has the usual passageway 4opening into the bowl to supply gasoline thereto, and a nipple 5 isattachedto the ends of the passageway to receive the end of the gasolinesupply tube. A valve 6 operated by a float 7 in a conventionalmanner-regulates the supply of gasoline to the carburetor. A mixingchamber 8 is formed in the body member and has a main inlet 9 for air.The'usual choke C, operated through connections (not shown) by the leverB, is provided. To this inlet, an air cleaner or other treating devicemay be attached, in the usual manner. The outlet of the mixing chamberis through the upper end of the casting as indicated at 10, and thisoutlet is controlled by the usual throttle valve 11. A venturi 12 ismounted in the mixing chamber between the inlet and the outlet. A supplytube 12 of conventional design communicating at its lower end with thefuel in the fuel chamber and having its outlet located adja- GEORGE E.BICKNELL, OF ST. LOUIS, MISSOURI, ASSIGNOR TO CARTER GARBURETOB cent tothe throat of the venturi serves as a the lever 15 is mounted a lever16. A pump cylinder 17 is supported on the side of the carburetor by anipple 18 screwed into the casting 1. The cylinder is fitted with apiston 19, and this piston is operatedfrom the lever 16 through aconnecting rod 20.

A suitable cap 21 is fitted to the top of the c linder, and a sheetmetal cover 22 is slidably mounted on aport 23 in the cap. The cover 22is provided with anopening 24 to receive the connecting rod 20, thusforming the dust cap for the cylinder 17.

The lever 16 and the throttle valve 11 are mounted on the shaft 14 atsuch an angle that the most rapid travel of the pump piston occursduring the early stages of the opening movement of the throttle. This isclearly illustrated in Figure 3 in which the reference numeral 16Aindicates the position of the lever 16 when the throttle is in theposition indicated at 11A, or substantially closed. The referencenumerals 16B and 11B represent the corresponding positions of thethrottle and lever when the throttle is about threequarters open, and16C and 11C indicate their positions. when the throttle is wide open. Itwill be noted upon inspection of Figure 3 that all of the downwardmovement of the.

piston has occurred between the closed position of the throttle and thethree-quarter open position, and that between the threequarter openposition and the full open position, the movement of the piston isslightly upward.

This arrangement is made to secure the desired rich mixture when thethrottle is partly open and to prevent an over-rich mixture when thethrottle is fully open. By the arrangement of the levers in thisposition, I am enabled to enrich the mixture at the particular pointthat the carburetor ordinarily supplies too weak a mixture, and thusobtain much more satisfactory operation.

The fuel pump is provided with a passageway 26 forming both inlet andoutlet. This passageway communicates with a passageway 27 in the nipple18 and a bore 28 in the body of the carburetor. lower end of the bore 28below the level of the fuel in the bowl is a body member 29 carrying acheck valve 30. This forms the inlet check valve of the pump. A secondbore 31 at an angle to the bore 28 has threaded therein a cage 32carrying a jet 33 and a ball check 34 forming the outlet check valve' ofthe pump. The jet 33 discharges into the mixing chamber 8 and is locatedto direct the stream of fuel into the mixing chamber.

and into the path of the flow of gas there through.

The piston of the pump is formed with an air bell, as shown. Threaded tothe lower portion of the air bell is an annular retaining member 35which retains the pump washer 36 in position. The annular member 35 isformed with a groove 37 to receive a spring Screwed into the 38 whichresiliently holds the washer 36 in engagement with the cylinder wall.The upper portion of the air bell is threaded as at 39 to receive amember 40 which is provided with a small bore 41. A lock nut 42 holdsthe member in position, as shown in Figure 4.

The inside of the air bell has a boss 48 carrying a bimetallicthermostat 44 secured by a suitable screw 45. A valve member 46 iscarried by the upper end of the thermostat and serves to form a closurefor the ends of the bore 41 when the temperature is low. The metals inthe thermostat are so arranged that the closure 46 will be held againstthe ends of the member 40 to close the bore.

41 when the temperature is low, and will be drawn away from the end ofthe member 40 when the temperature is high, to permit air to pass freelythrough the opening 41. The closure member 46 may be provided with ayieldable seating member of suitable material, if desired, such as acork or oiled silk facing.

The form of device shown in Figure 6 is similar to that 'shown inFigures 1 and 2, except that the thermostatic control device is omittedand the pump is provided with only a single ball check. Other slightdifferences are that the lever 16 is connected directly to the piston at19A instead of through a link as shown in Figures 1 and 2. The dust capis omitted and the piston oscillates in the cylinder as it reciprocates.

The pump shown in Figure '7 is similar to that shown in Figures 5 and 6,except that instead of the piston being provided'with an air bell, thepump cylinder-is formed with a skirt 46 surrounded by an annularpassageway 47, as shown. The attaching nipple 48 1s at the lower ortionof the cylinder, and the lower end of t e cylinder is closed by a plugit being directly connected through the bores 60 and 61 to the jet 33'.The inlet of the pump at 29' being considerably below the fuel level AAin the bowl 2', the fuel will normally displace the ball 30' before thelevel of fuel in conduit has fallen as low as the level i of the point62- at which the bores 60 and 61 communicate. While some air may besucked into the pump upon a rapid upward movement of the piston 19',this quantity will be negllg ble on account. of the small size of the etorifice 33'. By this arrangement, the

necessity for using an additional ball check is obviated.

The operation of the device is as follows:

The nipple 5 being connected to a suitablecourse of supply, the float 7permits the valve to remain open until the fuel has reached apredetermined level in the bowl 2. Upon startingthe engine, air is drawninto the inlet 9 through the mixing chamber 8 and the outlet 10, therate of its passage therethrough being controlled by the throttle 11.

Assuming that the throttle is in its closed position, as indicated at11A, the fuel will be drawn up through the idling tube and dischargedthrough an outlet 51 at the end of the throttle in the usual manner.When the throttle is open, the suction at the outlet 51 is reduced,while that in the throat 52 of the venturi is increased. The tubes 50and 13 being separately connected in conventional manner to a point inthe fuel chamber below the fuel level, the flow of fuelthrough theoutlet 51 will cease and the fuel level in the tube 13 will be drawn upto the mouth of the tube, from whence it will be carried. away by thestream of air passing through the throat of the venturi.

As the throttle is opened, the piston 19 will be moved downwardly in thecylinder 17, fuel will rise through the opening in the annular member 35and into the air bell 55. Assuming that the temperature is comparativelylow, the closure 46 will be seated against the end of the member 40,preventing the escape of air from the bell and causing it to becompressed therein by the fuel. It will be understood that the jet 33 isa very small orifice, the resistance of which sets up a back pressureagainst the operation of the pump. The fuel, of course, is alsodischarging from the jet and supplements the fuel supply in the mixingchamber as long as the piston is being forced downwardly by the openingmovement of the throttle. After the downward movement has ceased, theair compressed in the bell will continue to discharge fuel through thejet 33 into the mixing chamber, this being desirable for the reason thatthe acceleration of the car is subsequent to the opening of thethrottle, generally lagging behind it for an interval of severalseconds.

A supply of rich mixture during this period causes the car to acceleratemore rapidly and is highly desirable when the engine is cool, but whenthe engine is hot, the fuel vaporizes freely and a sufficient quantityis supplied without the operation of the pump. Under these conditions,the thermostat 44 moves to the left, as shown in Figure 4, and moves theclosure 46 out of contact with the end of the member 40, permittingcommunication of the air bell 55 with the atmosphere. When the pump isoperated, the comparatively free movement of air through the bore 41permits the piston to move downwardly without displacement of fuel fromthe pump cylinder, and the pump is practically rendered inoperative.

When the engine is running nearly full speed with the throttle nearlyopen, the normal supply of gasoline is sufficient for purposes ofacceleration, and it is not desired to augment the supply during themovement of the throttle from the three-quarters open to full openposition, even when the engine is cold. With the-levers connected asshown, the downward movement of the piston from the position 11B to 16Cof the operating lever is negligible, while the movement during theearly stages of the opening movement is quite ra 1 It will be seen fromthe above description that the supplementary supply device is entirelyseparate and distinct from the normal fuel supply means, the main supplyjet and the idling supply jet operating the same in a carburetor towhich this device is applied as they would in its absenceL It will alsobe noted that the jet 33 being of comparatively small dimensions willspray the fuel into the mixing chamber upon operation of the pump ratherthan supplying it in drops and comparatively large unbroken masses asmight occur if the pum were connected to discharge through one of t emain jets of the carburetor. It will .be understood that the inventionis susceptible of many modifications, and, accordingly, I do not wish tobe limited in my protection, except as set forth in the accompanyingclaims.

I claim:

1. In a carburetor, a fuel chamber, a mixture conduit, means fornormally supplying fuel from said fuel chamber to said mixture conduit,a valve for controlling the passage of mixture through said conduit, afuel pump for supplying additional quantities of fuel to said fuelconduit, said pump comprising a chamber in which fuel is segregated fromthe fuel in said first named chamber, a connection between said pump andsaid valve for operating the pump to discharge fuel upon a movement ofsaid valve,,an air chamber associated with said pump to receive aportion of said segregated fuel during said movement and to dischargesaid portion after said movement has terminated, said pump beingconstructed and arranged to be substantially inoperative at hightemperatures.-

2. In a carburetor, a throttle valve, a main fuel chamber, a fuel pump,a fuel chamber in said pump, means for operating said valve, meansoperable by opening said valve to discharge said pump, means operated byclosing said valve to draw fuel from said main chamber into said pumpchamber, means comprising an air chamber adapted to receive anddischarge fuel under pressure for continuing the discharge of said pumpafter the termination of such opening movement, and thermostatic meansfor reducing the quantities of fuel discharged by said pump as thetemperature increases.

3. In a carburetor, a throttle valve, an accelerating pump having acylinder, a compression chamber, said chamber containing air and beingadapted to receivev and discharge fuel under pressure, means for placingfuel in said chamber under pressure upon an opening movement of saidthrottle valve, thermostatic means gradually operable as the temperatureincreases for relieving said pressure, and pressure means rendering saidthermostatic means less effective in proportion to the speed ofoperation of said valve.

4:. In a carburetor, a throttle valve, an accelerating pump having acylinder, a piston, a fuel compression chamber in said cylinder, an airchamber in communication with said compression chamber, means forforcing fuel into said air chamber upon an opening movement of saidvalve, an opening in communication with one of said chambers, a closurefor said opening, and thermostatic means for operating said closure;

5. In a carburetor, a mixing chamber, an accelerating pump having anoutlet, a piston for said pump, a jet in communication with said outletand adapted to discharge fuel into said mixing chamber, an opening insaid piston through which the pressure may be relieved independently ofthe jet, a closure for said opening and thermostatic means for operatingsaid closure.

6. In a carburetor, a throttle valve, a mixing chamber, means normallysupplying fuel to said chamber, an accelerating pump connected tointermittently supply additional fuel to said chamber, means connectedto said valve for operating said pump upon an opening movement thereof,a piston for said pump having an air-bell, an opening in said bell, andthermostatic means for eontrolling said opening.

7. In a carburetor, a throttle valve, a mixing chamber, means normallysupplying fuel to said chamber, an accelerating pump, connected tointermittently supply additional fuel to said chamber, means connectedto said valve for operating said pump upon an opening movement thereof,a piston for said pump having an air-bell, an opening in said bell, aclosure for said opening, and thermostatic means for operating saidclosure.

8. In a carburetor, a throttle valve, a mixing chamber, a fuel chamber,means for con veying fuel from said fuel chamber to said mixing chamber,means operable by amovement of said throttle valve to supply additionalfuel to said mixing chamber comprising an accelerating pump, an air bellin communication with said pump, an opening in said air bell forcommunication with the atmosphere, and thermostatic means forcontrolling said opening.

9. In a carburetor, a pump, said pump comprising an expansible chamberhaving a movable wall, an orifice in said wall, and thermostatic meansfor controlling said orifice, said control means comprising a valvemounted at the inner side of said orifice and being adapted to be movedto closed position either by a decreasein temperature or by a suddenincrease in pressure.

10. In a carburetor, an accelerating pump, a piston for said pump havingwalls forming a. chamber in which air is contained and is adapted to becompressed, an orifice in one of said walls, and thermostatic meanscontrolling said orifice.

11. In a carburetor, a mixing chamber, a throttle valve controlling theoutlet of said chamber, means forming a constant level fuel chamber, afuelnozzle for supplying fuel to said mixing chamber at a point anteriorto said throttle valve, an idling tube for supplying fuel to said mixingchamber at a point adjacent said throttle valve, a fuel pump connectedto said throttle, said pump having a fuel discharge outlet discharginginto said mixing chamber at a point anterior to said throttle, said pumpcomprising a cylinder and piston of circular cross section fitted tosaid cylinder, and an air bell in said piston, said air bell beingadapted to receive fuel during the discharge stroke of said piston andto discharge said fuel after the termination of said discharge stroke.

12. In a carburetor, means forming a mixing chamber, means forming aliquid fuel chamber, means for maintaining liquid fuel at asubstantially constant level in said fuel chamber, a nozzle connectedwith said fuel chamber and adapted to discharge fuel into said mixingchamber, a fuel pump connected to receive fuel from said fuel chamber,said 1 fuel pump having an outlet connection terminating in a highlyrestricted orificedischarging into said mixing chamber, said pumpincluding a piston, an air chamber for receiving fuel underpressureduring the T discharge stroke of said pump and subsequently dischargingsaid fuel through said orifice after termination of said dischargestroke, means for sealing said pump and said air chamber to permit thebuilding up of pressure therein, a throttle valve controlling the outletof said mixing chamber, and means connected with said throttle foroperating said pump.

13. In a carburetor, means forming a mix- 1 ing chamber, a throttlevalve for controlling the outlet of said mixing chamber, means forming afuel chamber, means for maintaining a constant level of fuel in saidchamber,

a nozzle connected to said fuel chamber and 3 discharging into saidmixing chamber, an idle conduit connected to said fuel chamber anddischarging into said mixing chamber adjacent the throttle, said nozzleand said idle conduit being calibrated to supply sufpump comprising acylinder, a circular piston closely fitting the walls of said cylinder,means for admitting fuel from said constant level chamber to saidcylinder, a discharge conduit leading from said cylinder to said mixingchamber, and an air bell adapted to receive fuel under pressure duringthe discharge stroke of said pump and to discharge said fuel underpressure subsequent to the discharge stroke of said pump.

14. In a carburetor, means forming a mixing chamber, a throttle at theoutlet of said mixing chamber, means forming a fuel chamber, meansnormally supplying fuel from said fuel chamber to said mixing chamber, apump for increasing the normal supply of fuel to said mixing chamber,said pump comprising a cylinder, a piston'in said cylinder, said pistonfitting said cylinder tightly enough to develop substantial pressuretherein, an air chamber in said piston, said air chamber being incommunication with said cylinder and adapted to receive fuel during thecompression stroke thereof, said cylinder having a fuel inlet and arestricted fuel outlet and confrom said cylinder, said resilient meansoperating when said throttle is opened and held open to maintain thefuel in said cylinder under pressure until a predetermined quantity hasbeen discharged thrusaid restricted passageway, and an expansiblepacking for said piston to prevent the leakage of fuel during the periodin which it is held under pressure.

17 A device of the character described in claim 16 and in which saidpacking comprises nections for operating said pump in response trollingthe passage of mixture through said chamber, means for operating saidvalve, a pump, said pump comprising a cylinder and a tight fittingpiston therein, said pump being connected to be operated by a movementof said valve, a passageway in communication with the outlet of saidpump, a highly restricted orifice in the outlet of sa d passageway, andan air chamber in said piston connected to receive fuel during theoperation of said pump and to discharge it through said jet after saidpump has ceased to operate.

16. In a carburetor, means forming a mixing conduit having an air inletand a mixture outlet, a throttle valve controlling said mixture outlet,means forming a constant level fuel supply chamber, an acceleratingpump, said pump including a cylinder, passages for admitting fuel tosaid cylinder from said constant level chamber and for discharging fuelfrom said cylinder to said mixin conduit, said fuel admitting passageshavlng an inlet check valve and said fuel discharge means having ahighly restricted passageway, a piston in said cylinder, connections foroperating said piston in response to a movement of said throttle, saidpiston being constructed and arranged to draw fuel into said cylinderduring closing movements of said throttle and tending to discharge saidfuel in response to opening movements of said throttle, resilient meansyieldable in response to increased pressure in the cylinder to permitthe opening of said throttle at a more rapid rate than fuel can bedischarged

